Find the critical value zα/2 that corresponds to a 93% confidence level.

The critical value is used to compute the margin of error. (Margin of error = Critical value x Standard deviation of the statistic or Margin of error = Critical value x Standard error of the statistic).
If the statistic has normal sampling distribution, then the the critical value can be expressed as a t score or as a z score. 
α = 1 - (confidence level / 100)
α = 1 - (93 / 100)=1-0.93=0.07
The critical probability is: pc= 1 - α/2  pc=1-0.035=0.965
The critical value is 1.81.